1. Field of the Invention
The present invention relates to a motor-driven column apparatus, and more particularly, to a lower type motor-driven column apparatus that allows an MDPS (Motor Driven Power Steering) to be used in middle and large vehicles.
2. Description of Related Art
In general, MDPS (Motor Driven Power Steering) that is a motor-driven steering device assisting steering power by using power from a motor without using hydraulic pressure is commonly used in small-sized vehicles.
The MDPS is equipped with a decelerator composed of a worm-shaft/worm wheel rotated by a motor to assist steering force and a motor-driven column apparatus having a tilt/telescopic structure to implement and tilt and telescopic performance.
The motor-driven column apparatus simultaneously operates a tilt mechanism in telescopic transmission, such that load to the motor is increased, and the motor-driven column apparatus having the tilt/telescopic operation mechanism is called an upper type motor-driven column apparatus.
As described above, the load exerted in the motor is necessarily increased by the operation mechanism in the upper type motor-driven column apparatus, such that load operation noise is generated.
Not only small-sized vehicle, middle-sized and large-sized vehicles have been necessarily equipped with the MDPS due to the importance of reducing fuel in the vehicles.
However, the motor-driven column apparatus used with the MDPS is the upper type designed for small-sized vehicles, as described above, and there is a structural limit in using the MDPS with the upper type motor-driven column apparatus itself for large-sized vehicles.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.